In general, a washing machine with a drying function includes a main body formed in a predetermined shape, a drum installed in the main body, a tub for surrounding the drum and collecting the wash water, a driving motor for rotating the drum, a detergent container for supplying a detergent, a water supply tube connected to the detergent container, for supplying the wash water only or the wash water mixed with the detergent of the detergent container, a drain tube for externally discharging the wash water used in washing, and a pump and a drain hose connected to the end of the drain tube, for forcibly discharging the wash water.
In the washing machine with the drying function, after the laundry and the wash water are put into the drum, the drum is rotated so that the laundry can be dropped in the gravity direction and washed by friction with the wash water. Recently, the drum type washing machine does not only wash the laundry but also dries the laundry by the hot air.
The washing machines with the drying function are classified into a condensation type washing machine and an exhaust type washing machine. In the condensation type washing machine, the hot air generated by a heater is sent to a drum by a ventilation fan, for drying the laundry in the drum. After drying the laundry, the air in the drum becomes the high temperature high humidity air and flows to an exhaust hole communicating with a tub. A nozzle for spraying the cold water is installed at one side of the exhaust hole, for removing moisture from the high temperature high humidity air, and supplying the dry air to the ventilation fan again.
In the exhaust type washing machine, the hot air generated by a heater and a ventilation fan is passed through the laundry in a drum, and externally exhausted from the washing machine through an exhaust hole formed at one side of the washing machine. The exhaust hole is linked to a corrugated hose connected to a tub. In case a baby or a pet is kept shut up in the washing machine, the exhaust hole serves as a vent hole.
When the exhaust type washing machine with the drying function dries the laundry, lint (fine fluff) is generated from the laundry. The lint is circulated with the hot air in the drum of the washing machine, and externally discharged from the washing machine through the exhaust hole.
A structure for periodically collecting the lint generated from the laundry after washing is provided to prevent the lint from being accumulated on the exhaust hole of the washing machine. That is, a lint filter is mounted in the exhaust hole to prevent the lint from clogging up the exhaust hole in long time use of the washing machine.
In the conventional dryer, the exhaust hole passes through an outer wall. The initial state of the exhaust hole (in installation) passing through the outer wall is not checked. Therefore, an installer must arbitrarily judge whether the exhaust hole satisfies the minimum specification for the operation of the dryer.
The conventional dryer recommends filter cleaning in every use. However, the user does not carefully clean the filter due to inconvenience and complication of filter cleaning. The filter is gradually clogged by repeated drying, which increases the drying time or power consumption. When the filter is seriously clogged up, fine lint is not collected in the filter but floats and sticks to the laundry and the dryer and contaminates the laundry. Moreover, in the case of the exhaust type dryer, if the lint clogs the exhaust hole for externally exhausting the used air and interrupts flow of the air, the user cannot easily check clogging of the exhaust hole.
In addition, the conventional dryer can decide or check clogging of the exhaust hole, but cannot provide any information on the current clogging degree of the exhaust hole or the air passage.